Fundamental Limits to the Electrochemical Impedance Stability of Dielectric Elastomers in Bioelectronics
journal contributionposted on 2019-12-10, 16:02 authored by Paul Le Floch, Nicola Molinari, Kewang Nan, Shuwen Zhang, Boris Kozinsky, Zhigang Suo, Jia Liu
Incorporation of elastomers into bioelectronics that reduces the mechanical mismatch between electronics and biological systems could potentially improve the long-term electronics–tissue interface. However, the chronic stability of elastomers in physiological conditions has not been systematically studied. Here, using electrochemical impedance spectrum we find that the electrochemical impedance of dielectric elastomers degrades over time in physiological environments. Both experimental and computational results reveal that this phenomenon is due to the diffusion of ions from the physiological solution into elastomers over time. Their conductivity increases by 6 orders of magnitude up to 10–8 S/m. When the passivated conductors are also composed of intrinsically stretchable materials, higher leakage currents can be detected. Scaling analyses suggest fundamental limitations to the electrical performances of interconnects made of stretchable materials.